accuracy
This last equation, equation 11.8, we can use to find the rotation period, or the length of the day,
of an earth-like planet in the habitable zone of any star system, so it would be very useful.
12.0 Why The Historical Second And Physical Second Coincide And Why They Are
The Base Unit
We want to turn our attention to equation 11.5 and write it
12.1
Because it may tell us why 1 second is the basic unit of our quantum mechanical solution for the
Earth/Moon/Sun system, which happens to coincide with the the fundamental unit of time we
developed since ancient times in our calendar we have today.
Let us talk, first, about how we got the unit of a second to measure time. The Sumerians, who
were of the first to settle down from wandering and gathering, from following the herds and
hunting, who fired clay to make the first homes, developed a system of writing and mathematics,
and agriculture, some 12 thousand years ago, gave us our system of measuring time.
They made their system of counting base 60, called sexagesimal, or hexagesimal, where we use
today base 10. They chose base 60 because it is evenly divisible by so much:
1,2,3,4,5,6, 10, 12, 15, 20, 30,…
and, because there are 12 months in a year, approximately the number of new Moons in a year,
and there are 5 fingers on each hand, and 12 times 5 is sixty. Twelve as well is an important
number and they wanted to factor base twelve into their counting (duodecimal) where twelve is
very abundant too, divisible evenly by
1,2,3,4,6,…
So they divided the day into 12 hours and the night into 12 hours, so the time from sunrise to
sunrise and sunset to sunset was 24 hours. So the Earth’s rotation period to this day is divided
into 24 hours. Because they had a base sixty counting system, they divided each hour into 60
minutes, and each minute into 60 seconds. If we divide the Earth’s rotation period into 24
hours, and each hour into 60 minutes, and each minute into sixty seconds, we get the duration
of a second we have today.
Looking at equation 12.1 the velocity of the Moon is given by
12.2
And the velocity of the Earth is given by